1. Field of the Invention
The present invention relates to an ultrasonically driven surgical blade.
2. Description of Related Art
Ultrasonic knives are commonly used to cut and coagulate tissue. An ultrasonic knife assembly includes a blade that is coupled to an ultrasonic horn. The horn contains a transducer that is excited by an electrical source. The excitation of the transducer induces a corresponding vibratory movement of the blade. It has been found that the vibratory movement of the blade can increase the cutting and/or coagulation of tissue. Generally speaking, a sharp blade will increase the cutting efficiency of the knife, while a dull blade has been found to improve hemostasis.
U.S. Pat. No. 5,324,299 issued to Davison et al. discloses an ultrasonic blade which has a hook. The hook has a sharpened blade recess which terminates into a dull tip. The dull tip tends to grab and pull the patient tissue into tension, so that the sharp blade portion can more readily cut the tissue. Although potentially effective in cutting unsupported fatty tissue, the Davison blade would be relatively ineffective in cutting non-hydrogenous tissue.
U.S. Pat. No. 3,086,288 issued to Balamuth et al., discloses an arcuate shaped surgical blade which has a cutting surface that extends from the base of the blade to the blade tip. Although potentially efficient in cutting tissue, the sharpness of the entire blade works against coagulation. Additionally, the wide profile of the Balamuth blade does not allow the knife to be inserted into a trocar, thereby limiting the use of the blade in laparoscopic procedures. It would be desirable to provide a low profile ultrasonically driven blade that is efficient in both cutting and coagulating tissue, and has a profile that allows the knife to be inserted through a trocar.